The objective of the total project is to document the importance of membrane function during neoplastic transformation. Further, we want to know what happens to the membrane functions of cellular components of the immune system when the neoplastic process is initiated or already present. Membrane function is quantified by permeability coefficients for water and non-electrolytes; flux measurements define electrolytes and special nutrients like amino acids and monosaccharides. Methodology includes the use of isotopes for flux measurements and optical and electronic devices to monitor changes in cell volume. Models of membrane function are generated with the help of analog/digital computers and serve to explain how the cell controls its internal economy, growth and division. Our overall objective is to prepare a set of membrane parameters for the neoplastic cell of leukemia and to determine similarities and differences between the neoplastic cell of leukemia and the immature and mature components of the myeloid line. We wish to establish a similar set of parameters for the cellular components of the immunological surveillance system as a functional basis for its reactivity.